This invention relates to a disposable undergarment for absorption and containment of body excretion.
Japanese Patent Application Publication No. 2000-14699A discloses a disposable undergarment of open-type comprising an elastically stretchable base sheet, a liquid-pervious topsheet smaller than the base sheet and a liquid-absorbent panel disposed between these sheets. The base sheet is composed, in a longitudinal direction, of a front waist region, a rear waist region and a crotch region extending between these waist regions. The crotch region is formed along its transversely opposite side edges with transversely opposite side edge portions curving transversely inward so as to describe circular arcs and intended to define leg-holes. According to the disclosure of the above-identified Publication, the base sheet is formed of elastically stretchable stock material to ensure a good fit of the base sheet around the wearer""s torso and thighs and thereby to prevent body excretion from leaking beyond peripheral edges of a waist-hole as well as a pair of leg-holes without any elastic members attached to the undergarment in associated with the waist-hole as well as with the leg-holes.
Generally, it is required for the disposable undergarment absorbing and containing body excretion to ensure the transversely opposite side edge portion intended to define the leg-holes"" each having a circumferential dimension smaller than that of the waist-hole""s peripheral edge to fit around the wearer""s thighs sufficiently to prevent body excretion from leaking through the peripheral edges of the leg-holes. However, the above-identified Publication discloses no measure to improve the fit of the transversely opposite side edge portions intended to define the leg-holes around the wearer""s thighs. With the undergarment disclosed therein, a dimension by which the undergarment is stretchable as the undergarment is put on the wearer""s body is larger in the area surrounding the wearer""s torso than in the transversely opposite side edge portions intended to define the leg-holes surrounding the wearer""s thighs and these transversely opposite side edge portions can not fit around the wearer""s thighs with sufficiently high stretch stress to ensure a desired leak-barrier effect.
It is an object of this invention to provide a disposable undergarment that is designed so transversely opposite side edges portions of the undergarment intended to form leg-holes and having elastic stretchability can sufficiently fit around the wearer""s thighs to prevent body excretion from leaking through peripheral edges of the leg-holes.
According to this invention, there is provided a disposable undergarment comprising a substantially liquid-impervious base sheet having elastic stretchability, a liquid-absorbent panel attached to an inner surface of the base sheet, a front waist region, a rear waist region and a crotch region extending therebetween, and the crotch region being formed along transversely opposite sides thereof with transversely opposite side edge portions intended to define leg-holes curving transversely inward so as to describe substantially circular arcs.
The base sheet is folded back at least once onto itself along the transversely opposite side edge portions intended to define the leg-holes, a basis weight of the base sheet in the transversely opposite side edge portions intended to define the leg-holes being higher in the transversely opposite side edge portions than in a remaining area of the base sheet, and a tensile stress of the base sheet being higher in the transversely opposite side edge portions than in the remaining area of the base sheet.
According to one embodiment of this invention, a substantially liquid-impervious elasticized cover sheet is placed on a inner surface of the base sheet so as to cover a substantially entire area of the base sheet and has at least one opening being relatively large in the longitudinal direction with a peripheral portion joined to a peripheral portion of the base sheet, and wherein the cover sheet is folded back at least once onto itself and joined together along the transversely opposite side edge portions intended to define the leg-holes so that a basis weight of the cover sheet is higher in the transversely opposite side edge portions intended to define the leg-holes than in a remaining area of the cover sheet and a tensile stress of the cover sheet is higher in the transversely opposite side edge portions than in the remaining area of the cover sheet.
According to another embodiment of this invention, the cover sheet is folded back at least once onto itself along the peripheral edge portion of the opening so that a basis weight of the cover sheet is higher in the peripheral edge portion of the opening than in a remaining area of the cover sheet and a tensile stress of the cover sheet is higher in the peripheral edge portion of the opening than the remaining area of the cover sheet.
According to still another embodiment of this invention, a bulging seam formed on the cover sheet extends in the longitudinal direction in vicinity of a longitudinal center line of the cover sheet and the bulging seam is formed by joining the inner surface of the cover sheet.